Gulf Intracoastal Waterway - Louisiana Route Segment

Lake Borgne, LA to Sabine River, LA

Louisiana’s section of the Gulf Intracoastal Waterway (GICW) begins near the mouth of the Pearl River, MS near (MM "41.0 EHL") at 30°15.042’ N / 88°23.666’ W in Lake Borgne.

From Lake Borgne, this section of the GICW runs generally in a westerly direction for 307.0 miles ending at 30°03.2’ N / 93°43.2’ W (MM "266.0 WHL") on the Sabine River at the Texas state line.

Navigation

Buoyage

Louisiana’s GICW is marked with your standard Aids to Navigation which also display yellow triangles or yellow squares. When westbound along Louisiana’s Gulf Intracoastal Waterway, marks displaying yellow triangles should be kept on your starboard hand and those marked with yellow squares should be kept to port.

While typically the yellow triangles will be found on red markers and yellow squares are found on green markers, caution should be exercised along this route in the vicinity of the Mississippi River, Lower Atchafalaya River, Vermilion River, and Calcasieu River where the GICW intersects or coincides with the channels marked by the Lateral Buoyage System.

Charts

NOAA chart coverage of this portion of the GICW beginning at (MM “41.0 EHL”) to (MM "266.0 WHL" is provided by charts #11367, #11365, #11355, #11350, #11348, and #11331. These charts can be viewed by clicking on the links below:

Distances and Mileages

All distances along the Louisiana’s Gulf Intracoastal Waterway are given in statute miles unless otherwise noted. Statute miles are used in order to conform to the distances shown on the small craft charts typically used along this route.

This portion of the GICW between the Mississippi State line and the Texas State line is measured based on both decreasing and increasing mileage East and West of Harvey Lock from (MM "41.0 EHL") to (MM "266.0 WHL").

Channels

The Federal project depth for the Louisiana portion of the Gulf Intracoastal Waterway provides for a minimum channel depth of 12 feet. Even though every effort is made to maintain the project depth, the actual controlling depths in the channels may vary due to shoaling reducing the available water depth until maintenance dredging can be accomplished.

Communications

All operating bridges in Louisiana guard VHF Channel 13. The locks found within the state guard either channel 14 or channel 13.

The U.S. Coast Guard advises all vessels to exercise caution in any area where the GICW intersects major shipping channels. A “Security Call” on VHF channel 13 is requested prior to crossing any shipping channels, especially during periods of restricted visibility.

Locks

Louisiana Gulf Intracoastal Waterway Locks

Operates within the operating times of the Florida Avenue, Claibourne, and St. Claude operating bridges.

14

0.0

Harvey Lock

On Demand

14

93.0 WHL

Bayou Boeuf Lock

On Demand

14

163.0 WHL

Leland-Bowman Lock

On Demand

14

238.2 WHL

Calcasieu Lock

On Demand

13

Overhead Power Lines

Quite a few overhead cables cross Louisiana’s Gulf Intracoastal Waterway. Numerous cable crossings with a minimum authorized clearance noted at 90’ are located between (MM "34.0 WHL") and (MM "135.0 WHL"). (1) overhead cable at (MM "219.9 WHL") has been reported to have a clearance of only 82’.

Caution - Many of the overhead cables over the waterway carry high voltage, and an extra margin of safety should be allowed when the weather is threatening.

Tides

Tidal ranges are fairly small along Louisiana’s coast. Under normal conditions the mean range of tide averages between less than 0.5’ at Chef Menteur Pass to about 0.5’ across the remainder of the state to the Texas State line.

Louisiana experiences (2) types of tides; from the Mississippi state line west to Vermilion Bay the type of tide experienced is commonly refered to as a "Diurnal Tide" - exhibiting (1) high tide and (1) low tide each day. West of Vermilion Bay to the Texas State Line, a "Mixed Tide" gradually takes over having (2) unequal high and low tides each day.

Inlets & Passes

There are more than (31) Passes (Inlets) between the Gulf of Mexico and the inside waters of Louisiana. Most of these are only suitable for shallow draft vessels or local knowledge, but some can be considered navigable by most vessels.

Chef Menteur Pass

Chef Menteur Pass, a pass between Lake Borgne and Lake Pontchartrain also intersects the GICW at (MM "22.9 EHL") about 1.7 miles above the entrance. While the pass itself is deep with good water almost bank to bank, the seaward approach to the pass has a least depth of 6 feet. A new Gulf Intracoastal Waterway alignment channel crosses Chef Menteur Pass 1 mile SE of the original Intracoastal Waterway crossing.

Southwest Pass

Southwest Pass, the westernmost of the passes for the Mississippi River. The entrance has jetties on both sides with the East Jetty marked by the Southwest Pass Entrance Light (Fl 10s) and is equipped with a RACON showing (-‧-). The approach channel to Southwest Pass is marked by a lighted buoy Mo (a), 1.6 miles south of the entrance.

Southwest Pass is deep and well-marked by daybeacons and ranges to the Head of Passes. Above the Head of Passes the channel is marked both by daybeacons and a few buoys, but with few exceptions deep water is available bank to bank.

Intersection with the Gulf Intracoastal Waterway happens abeam of the Inner Harbor Navigation Canal 112.6 miles above the entrance.

Cat Island Pass

Cat Island Pass is well marked with lighted buoys, daybeacons, and ranges. It has a controlling depth of 13’, but minimum depths of 15’ have been noted. Cat Island Pass intersects the Houma Navigation Canal 1.5 miles above the entrance. From the Houma Navigation Canal, the least depth reported was 10’ to its intersection with the GICW at Houma, LA at (MM “59.6 WHL”), 36.8 miles above Cat Island Pass.

Atchafalaya Bay Inlet

Atchafalaya Bay Inlet is located between Point au Fer Island to the west and Eugene Island to the west. It is deep (20’) and well-marked by buoys and daybeacons. Point au Fer Light is the most prominent navigation aid in the area.

From the entrance, a dredged channel leads to the Lower Atchafalaya River and on to its intersection with the Gulf Intracoastal Waterway at (MM “98.2 WHL”) 26.9 miles above the entrance.

Calcasieu Pass

Calcasieu Pass is a deep-draft channel leading to Lake Charles, LA. It is deep with a minimum controlling depth of 33’ and is well-marked with buoys, daybeacons and ranges. The entrance is protected by jetties. The approach channel is marked by a fairway buoy RW “CC” showing a Mo (A) white light.

Louisiana GICW Charts

Waterway Guide 2017 Southern Edition (Louisiana GICW)

Waterway Guide Southern Edition is a must for exploring Florida's East coast, the St. John's River, the Okeechobee Waterway, the Keys, Florida's West coast and the Gulf of Mexico to Brownsville, Texas. This guide features mile-by-mile navigation information, aerial photography with marked routes, marina listings and locator charts, anchorage information and expanded "Goin' Ashore" articles on ports along the way.